diff --git a/problems/0494.目标和.md b/problems/0494.目标和.md index 99b76834..929b97d4 100644 --- a/problems/0494.目标和.md +++ b/problems/0494.目标和.md @@ -351,6 +351,28 @@ const findTargetSumWays = (nums, target) => { }; ``` +TypeScript: + +```ts +function findTargetSumWays(nums: number[], target: number): number { + // 把数组分成两个组合left, right.left + right = sum, left - right = target. + const sum: number = nums.reduce((a: number, b: number): number => a + b); + if ((sum + target) % 2 || Math.abs(target) > sum) return 0; + const left: number = (sum + target) / 2; + + // 将问题转化为装满容量为left的背包有多少种方法 + // dp[i]表示装满容量为i的背包有多少种方法 + const dp: number[] = new Array(left + 1).fill(0); + dp[0] = 1; // 装满容量为0的背包有1种方法(什么也不装) + for (let i: number = 0; i < nums.length; i++) { + for (let j: number = left; j >= nums[i]; j--) { + dp[j] += dp[j - nums[i]]; + } + } + return dp[left]; +}; +``` + -----------------------